Ignition System

Question 1

What are the different modes for ignition?

Answer 1

• Normal - Automatic ignition supplied during engine start (with throttles out of cutoff), and whenever engine anti ice is selected
• ON - Continuous ignition (regardless of throttle micro-switch position, anti-icing, or start control relay position)

Question 2

Break down the Exciter box

Answer 2

• Two exciters per engine
• One o’clock on engine casing
• Converts 28 VDC to 3,100 volts at 3 amps and sends to igniters
• Green ignition light on whenever the exciter box is powered

Question 3

Break down the Spark Igniters

Answer 3

• Two each engine (5 and 7 o’clock positions)
• Malfunction of one doesn’t affect the other
• Spark rate is 1-4 sparks per second

Question 4

Explain the main usage for ignition mode “Normal”

Answer 4

• Engine Start
• Use of engine anti-ice
• Other routine operations

Question 5

Explain the main usage for ignition mode “ON”

Answer 5

• Takeoffs and landings
• Emergency air restart
• Emergency descents
• Stalls
• Severe turbulence
• Heavy Rain

Question 6

What does the engine synchronizer do?

Answer 6

Synchronizes the engine, gets rid of the wa wa wa wa sound heard from the cabin.

Question 7

How does the control box for the Engine Synchronizer work?

Answer 7

• Receives ac signals from N1 and N2 tach-generators, then adjusts right (slave) engine
• N1 range - RPM +/- 1.5%
• N2 range - RPM +/- 1%
• Master signal from left engine
• Speed setting actuator in right nacelle

Question 8

Clarify what each operation setting does for the Engine Synchronizer.

Answer 8

• ON - Synchronization Indicator will illuminate
• OFF - Actuator centers and light extinguishes

Question 9

Should the Engine Synchronizer be on or off for takeoffs and landings?

Answer 9

OFF

Question 10

Lack of synchronization is most noticable where?

Answer 10

Rear seats - N1
Cockpit - N2